Super-typhoon Nanmadol strengthened overnight as it moves north of the Philippines, killing one, flooding several towns in the northern and central Philippines and forcing hundreds to evacuate.

The government raised its highest storm warning in the northern province of Cagayan as Typhoon Nanmadol, locally known as Mina, intensified.

Nandmadol was northeast of Aurora as of 4 p.m. Manila time, the Philippine Atmospheric, Geophysical & Astronomical Services Administration said on its website. It has maximum sustained winds of more than 100 mph, and gusts of up to 150 mph, the agency said.

Public storm warning signal 4 was hoisted in Cagayan, which could result in “severe losses” for rice and corn plantation, disrupt electricity and telecommunication services and “severely” damage residential buildings made of mixed construction materials, the weather bureau said.

TV footage showed farmers in northeastern provinces reinforcing dikes in rice paddies with sandbags while floodwaters swamped several towns.

The coast guard has grounded vessels and warned of waves about 5 meters high extending to Manila Bay.

An extended forecast track shows Nanmadol weakening slightly east of southern Taiwan by Monday morning.